The present invention relates to a dialog system, a dialog system execution method and a computer memory product which permits smooth communication of information between a computer and a user.
With the recent rapid improvement in the processing ability of computers and the popularization of communication environments such as the Internet, the users have increasing opportunities to acquire information through computers, and the computers have increasing opportunities to notify the users of information. Hence, it is urgent to develop dialog interfaces that allow not only engineers having a thorough knowledge of computers but also ordinary home users who are not necessarily familiar with computers to receive various information services while communicating with a computer.
A dialog system for providing various information services sets a dialog procedure corresponding to a specific service. Setting a dialog procedure for each individual service requires the developer of the dialog system to perform complicated work, and consequently the development cost of the dialog system increases. Nowadays, therefore, many dialog systems having a general-purpose dialog scenario applicable to a large number of services have been developed.
For example, user's input information inputted from an input unit and output information (screen or voice information) outputted to an output unit, and the system's processing procedure for the user's input information are written in a dialog scenario. By applying the dialog scenario to a plurality of services, there is no need to set a dialog procedure for each individual service.
Typical examples of languages for writing a dialog scenario include HTML that realizes a dialog using a screen, and VoiceXML that realizes a dialog using voice. Moreover, not only description languages for realizing a single modality, for example, a description language dealing with only the screen or voice, but also description languages such as X+V and SALT for realizing multi-modality including a combination of screen and voice, and description languages such as XISL extendable to applications other than screen and voice are used (see Japanese Patent Application Laid-Open No. 8-234789 (1996)).
A dialog scenario is composed of expression data representing expressions to be outputted to the user by the dialog system, recognition data for receiving an input from the user, and execution procedure data that is the procedure of executing an expression and an input. In the case of VoiceXML, for example, a prompt indicating a character string subjected to voice synthesis is written as expression data, a voice recognition grammar is written as recognition data, and the procedure of executing prompt output and voice recognition is written as execution procedure data.